DLuders

If you use 6 ea. new AA, 1.5V Alkaline batteries in the common 8881 Power Functions Battery Box, you will initially get a full 9V (good for high-torque applications). If you use 1.2V Rechargeable AA batteries, you will only get 7.2V but you can recharge them over and over for long-term economy. Even the 8878 Rechargeable Power Functions Battery Box only delivers 7.4V. When you ask what is "best", it depends on whether you need MAXIMUM POWER or not. From Philo's Power Functions Motors Power Curves webpage, you can see the effect that low voltage has on Mechanical Power. Here's the effect using either the Version 1 PF Receiver or the newer v2 PF Receiver) -- you're giving up at least 1/4 of possible Mechanical Power by using Rechargeable batteries:

Those 11x11 Hemisphere parts come in many flavors!

The step-by-step Building Instructions for Mahjqa's "Intermediate Power Functions Chassis" (which he showed in a slideshow above) can be found in his Flickr photoset. I built one, and it's a great platform for Lego Technic Allround Car Competition vehicles! All of his Building Instruction images have been compiled into a single PDF document that you can download via SkyDrive here.

madoca1977 posted this of a Lego Technic Sliding Axle Power Take-Off (PTO):

On the Lego Technic Designers Blog, Uwe Wabra posted this information about the 42000 set: "February 27, 2013 New Grand Prix Racer 42000 combines the best of everything What is your favorite feature in the 42000 Grand Prix Racer? That we managed to get it so close to what a racer looks like in real life. It was a challenge but I'm very happy with the result. Is it based on an existing race car model? No. We studied a wide range of racecars, and we took the best of all worlds and combined it into this model. What can it do? We have new elements, like the wheel bearings. The front wheel bearings are different from the back wheel bearings, and the tires are new as well. We had a high focus on optimizing the suspension, and the new bearings really made it possible for us to get it just right.We tested different designs for the suspension and durability in our test center, and the solution we ended up with is very strong. Both front and back. Some other functions that make it very realistic are: - The adjustable rear spoiler - V8 engine with moving pistons (if you lift the top, you have a full view of the engine) - Optimized steering - You can upgrade the model with Power Functions (by using the 8293 Power Functions Motor Set). This will motorize the adjustment of the rear spoiler and the opening of the motor cover. And the B-model? It's an awesome racing truck with the same qualities that make the Racer unique. And of course you can always design your own racer, and upload a picture of it in the Gallery!"

Lipko's Red Coupé V12 has been added to Rebrickable. AFOLs who already own the 8070 Super Car set have 48.2% of the required 2,089 parts. Thanks for sharing your MOC, Mate!

@ Paul B: You could go to your local Carpet Store and get some of the used cardboard rolls that once held carpeting. You can usually find them outside next to the trash dumpster. If you use a saw to cut them up into "logs", then glue them together (either horizontally or vertically), they would form a relatively lightweight and inexpensive obstacle course.

Maybe The Lego Group should just produce one of Paul Boratko's fine supercar MOCs (with his permission, of course), and call it the 42003!

@ Nicklord: You can already buy the desired Lego Power Functions elements (if that's what you mean by "RC") on If this Shop.Lego.com webpage (do a "Change Region" at the top-right corner to match your country/language). If you can wait a few weeks, (sometime in March 2013) the Power Functions L-Motor, Servo Motor, and v2 PF Receiver will be available for sale by The Lego Group. It is more efficient to buy the needed PF elements rather than buy a bunch of sets with parts you don't need/want.

Zblj's "The Black Wolf" has been added to Rebrickable.

@ bacem: A Lego set's "B-Model" is the alternate model of a "2-for-1" set. Lately, the alternate Building Instructions are posted on the Lego Customer Service Building Instructions webpage.

I would buy your desired parts from Bricklink.com -- you get exactly what you want (and nothing more). You can even shop for the best price worldwide in most cases.

@ Bubble: Get the 8043 Motorized Excavator -- it's out of production now and is much more fun than the 9398 4x4 Crawler set (which is still in production).

@ duckworthd: Welcome to Eurobricks! Had you seen the capabilities of Rebrickable yet? It has the ability of importing Brickstore BSX files and then scanning available Bricklink stores for parts for MOCs like that huge Lego Rex v2: Image

Nice! If you put one of these on a Lego Pinball machine, you'd have a hard time keeping up with all of the balls coming down to the flippers!

@ TasV: Welcome to Eurobricks! If you look on this post earlier in this same topic, you can see pictures of the four Rok Lox Micro Comp Tires mounted on the 56145 "Wheels 30.4mm D. x 20mm with No Pin Holes and Reinforced Rim". They are VERY GRIPPY and you will be pleased with them.

No, I don't think there is a missing Lego piece. The gray 3L Technic Pin with Stop Bush is merely acting as a "spacer" between the two yellow Technic Liftarms. One does not need any connection between the two liftarms to be stable; there only needs to be Technic Pins protruding from both liftarms.

@ Samanen: Nice collection! What's that Homer Simpson doll doing on the top shelf with that black tow truck?

@ bacem: Why don't you attach your LDD .lxf file to your post, so that others can "fix" it and then post it for you to continue with?

@ lotusman: iLeGos (from Florida USA) sells 10 ft (305cm) lengths of Lego-compatible pneumatic tubing here.

@ bacem: I looked at the 6229's Bricklink Part Inventory to see what is SUPPOSED TO fit on that 98590 torso part. The 90641 "Hero Factory Armor with Ball Joint Socket - Size 3" (first picture below) is supposed to be the XT4's upper arms. I could fit it on any of the 5 ball joints on the torso piece in LDD, if it was rotated in a certain orientation. The 98587 "Hero Factory Mask, One Eye Opening (XT4)" (second picture below) is not in LDD. The 90641 piece cannot fit on the 3-Technic-Pinhole-from-the-top's Ball Joint because the "wings" of the 90641 part seem to strike other areas of the torso piece in LDD. I don't have a real torso piece to test this out in real life to see if it's SUPPOSED TO fit.

@ VMLN8R: Thanks for making the LDD .lxf file! Now there can be many motorized Lego Manta Rays swimming in the seas:

@ bacem: The Lego Hero Factory 6229 XT4 set has the 98590 "Black Hero Factory Torso, Extra Small with Ball Joints": You did not specify which program you were using. If you're talking about Lego Digital Designer (LDD), the 98590 part DOES allow a Lego Technic Pin to be inserted into all of the holes. I just tried it, and there is no "bug" in LDD with this part. To access ALL of the available parts in LDD, when you open the program, click on the black tab that says "Lego Digital Designer EXTENDED." The other two tabs (the blue "Lego Digital Designer" tab and white "Lego Mindstorms" tab) don't have all of the available parts.

@ SheepEater: When Conchas drove his 9398 4x4 Crawler on the beach, sand gummed-up the Portal Axle hubs and caused a lot of friction. One could separate the hubs using a Butter Knife to clean out the sand, using the technique on this :